Automatic external defibrillators have been in use for a number of years to treat individuals stricken with sudden cardiac arrest, one of the largest causes of death in the United States. Sudden cardiac arrest (SCA) most often occurs without warning, striking people with no previously recognized symptoms of heart disease. It is estimated that more than 1000 people per day are victims of sudden cardiac arrest in the United States alone. SCA results when the electrical component of the heart no longer functions properly causing an abnormal sinus rhythm. One such abnormal sinus rhythm, ventricular fibrillation (VF), is caused by abnormal and very fast electrical activity in the heart. As a result, the heart fails to adequately pump blood through the body. VF may be treated by applying an electric shock to a patient's heart through the use of a defibrillator. The shock clears the heart of abnormal electrical activity (in a process called “defibrillation”) by producing a momentary asystole and providing an opportunity for the heart's natural pacemaker areas to restore normal rhythmic function. When delivered external to the patient, these electrical pulses are high energy pulses, typically in the range of 30 to 360 Joules of energy.
Defibrillators have undergone an evolution over the past decade. Originally defibrillators were manual devices requiring both medical and technical expertise to operate. A physician would carefully set the controls of the defibrillator to apply a shock which diagnosis of the patient or experience with other patients in similar conditions indicated to be most likely to be effective. Following many years of experience with manual defibrillators and motivated by advances in microprocessing and signal analysis, defibrillators have become more automated to the point where a two-pad electrode attached to a patient's chest can detect and diagnose VF and deliver an appropriate shock through the chest wall. However such automated defibrillators continued to be prescription devices used by medical professionals or under the auspices of a controlled emergency response program as described in U.S. Pat. No. 6,694,299. In the final months of 2004 AEDs have reached a level of sophistication and reliability which now enables them to be sold to laypersons without prescription, as over-the-counter (OTC) medical devices. AEDs may now be sold through retail channels (stores, websites, catalogs) and purchased by anyone for use at home in the event of a sudden cardiac arrest emergency.
Prescription AEDs given to patients by physicians or used in institutions such as hospitals, airports, office buildings, and emergency response organizations are initially handled by trained medical professionals. When these medical professionals receive an AED the electronic unit is boxed together with electrode pads, instruction guides, and a battery pack. The AED and its accessories are assembled by the medical professional including the installation of the battery pack into the battery compartment of the AED. The AED is then powered up and performs a self-test. An OTC AED, on the other hand, is purchased and initially handled by a consumer, and needs no intervention by a medical professional. This means that the consumer can face the task of assembling the OTC AED and getting it ready for use without any professional help. This is a prospect of considerable concern, for it is essential that the OTC AED be fully operational when it is needed to save a life. One solution to this dilemma is to sell the OTC AED to the consumer in a fully assembled state. However a fully operational AED will generally be performing periodic self-testing to continuously assure its operability. This presents the prospect of an OTC AED alarming during shipment to the retail outlet if the self-testing identifies a problem that needs to be addressed. An OTC AED alarming in a shipping container in an airport or other transit facility or carrier could be very disruptive to the facility or carrier personnel who are unaware of its presence. This makes shipment of fully operational AEDs by common carrier inadvisable. It is desirable, then, for an OTC AED to be easy to prepare for use by a layperson without professional medical guidance.